In Plato's Theaetetus, Socrates engages Theaetetus, and to a lesser extent Theodorus, in a somewhat playful dialogue that closely examines the idea of knowledge. Multiple critiques of different theories of knowledge leave the trio with no solid idea of what knowledge may be, but, much to the contrary, they establish some specific ideas about what knowledge cannot be. While this process may or may not constitute the attainment of some particular pieces of knowledge, Socrates does at least hint that the dialogue has brought to light certain obstacles, if not to knowledge, then perhaps to a less distorted worldview, or the ability to think clearly. Regardless of any certainty in regard to what may constitute knowledge, the Theaetetus seems to suggest that certainty itself, as long as close inspection reveals it to be illusory, may obstruct clear cognition.
At first glance, one may find it difficult to distinguish between the terms 'certainty' and 'clear cognition.' By 'certainty,' I intend to suggest a subjective experience, such that one may feel certain about something that may in fact contradict reality. One need only point to any instance of disillusionment in order to make a case for such tendency in human experience. 'Clear cognition,' on the other hand, implies a correspondence between one's experience and external events. When one develops a sense of certainty about something that contradicts reality, then, far from the two terms being synonymous, certainty in fact interferes with clear cognition.
Socrates and Theaetetus offer different theories of knowledge, all of which prove to be problematic, at least individually. First, Theaetetus attempts a definition by enumeration of different types of knowledge (146d). Socrates refutes this suggestion, on the basis that it merely lists things that one may have knowledge about, rather than explains what knowledge consists of (147c). Theaetetus next puts forth Protagoras' theory that knowledge is perception (151d). According to Socrates' and Theaetetus' reading of this theory, each individual person establishes what is and is not according to how one perceives things. After long consideration of this theory, Socrates finally refutes it on the basis that the kinds of properties that knowledge makes use of, such as being and likeness, are not restrained to any given sense, so that some other part of a person, namely the soul, must consider them without the aid of another instrument. The eyes, for example, perceive shapes and colors, whereas the ears perceive sounds, and so on so that each sensory organ perceives a different kind of thing. However, since one may consider the objects of each sensory perception in terms of being and likeness, it must be the case that one uses a different faculty than those of sensory perceptions in order to consider such things as being and likeness (184b- 186e).
The conversation moves next to the theory that knowledge is true judgment. This theory does not succeed, since an orator in court will try to persuade the jury to agree with him as well as he can, whether or not he has any way of knowing what has actually happened. Even if the jury arrives at a true judgment about a particular case, the true judgment may be entirely random in regard to its relationship to the actual events that concern it. True judgment therefore turns out to seem more like a guess than knowledge (201c). Finally, Theaetetus suggests that knowledge may be true judgment with an account. However, their failure to imagine what may adequately constitute an account makes this theory fail as well (201c- 210a). By the end of the dialogue, the participants have no solid idea as to what may constitute knowledge.
Throughout the dialogue, Socrates repeatedly asserts his own lack of knowledge. He suggests that he has a role in the discussion similar to that of a midwife who assists a pregnant woman in childbirth. In accordance with this metaphor, he bears no knowledge himself, but merely serves to help Theaetetus to develop and draw out his own knowledge (149a- 150d). At the end of the dialogue, after they have debunked the four theories of knowledge, Socrates asks Theaetetus if he is pregnant with any more thoughts about knowledge, or if they have all been delivered. After Theaetetus concedes to have nothing more to offer, Socrates refers to the thoughts as 'wind eggs,' by which term he suggests that they are not worth bringing up, or further developing theoretically. In his last words in the dialogue, Socrates says:
And so, Theaetetus, if ever in the future you should attempt to conceive or should succeed in conceiving other theories, they will be better ones as the result of this enquiry. And if you remain barren [of thoughts about knowledge], your companions will find you gentler and less tiresome; you will be modest and not think you know what you don't know. This is all my art can achieve--nothing more (210c).
The first line of this passage carries an ambiguous message. It remains unclear whether further theories might finally establish the truth about knowledge, or whether they will merely be better theories than the ones Socrates and Theaetetus have tested. Indeed, we should not expect Socrates to know whether other theories may arrive at the truth, since the Theaetetus does not provide any evidence that he would know such a thing. The rest of the passage reads more explicitly. Socrates makes it clear that certain theories, such as the ones they have critiqued, can cause people to feel certain about things that are not true.
However, it does not follow from their admitted ignorance of what constitutes knowledge that knowledge does not exist, or even that neither of them has knowledge, even though Socrates asserts that he in fact does not. Indeed, if in fact he does not know what knowledge is, it seems quite impossible for him to assert that he has none. (The assertion seems even stranger given that he provides the content for most of the dialogue.) In any case, although the dialogue has not disproved all knowledge, it does seem to assert very clearly a certain danger about faulty knowledge claims. Such claims, the dialogue has shown, may represent a sense of certainty that can interfere with true knowledge, if indeed such a thing exists; the dialogue, in any case, does seem to leave open the possibility.
This seems consistent with an idea that Socrates and Theaetetus touch on when they approach Protagoras' theory of knowledge from a Heraclitean point of view. Theaetetus agrees with Socrates' proposal that motion is healthy for, among many other things, the soul. By learning and studying, the two of which Socrates designates as motions, the soul gains knowledge and is preserved, whereas at rest it fails to acquire knowledge and forgets what it has learned (153c). One may draw the connection that certainty, insofar as it offers a sense of closure, may induce one to end a search for particular knowledge, and thus constitutes a mode of rest for the soul. In this way, certainty may pose an obstacle to learning, and to the soul's health.
At another point in the dialogue, Plato beckons Theodorus to participate actively in the dialogue:
Look at the company then. They are all children but you. So if we are to obey Protagoras, it is you and I who have got to be serious about his theory. It is you and I who must question and answer one another. Then he will not have this against us, at any rate, that we turned the criticism of his philosophy into sport with boys (168e).
Socrates says this after having imagined himself as Protagoras, in order to give voice to some objections that the real Protagoras might have had against Socrates' approach to the argument. Among these objections, Socrates acknowledges his advantage over Theaetetus, Protagoras' theory's defender, given that Theaetetus is so young. Theodorus repeatedly insists that he is too old to contribute substantially to the discussion. At one point, in accordance with the association between active thought and motion, he specifically describes himself as having "grown stiff" (162b). In the passage above, however, Socrates insists that Theodorus must not simply leave the activity of thought to other people. In light of the rest of the dialogue's content, this seems to assert that it is important for people not to simply let their minds come to rest about philosophical issues, but rather to keep their minds active so that they remain able to think critically.
This reading may help to explain Plato's decision to focus so explicitly on Protagoras' theory of knowledge. Not only did Protagoras' theory gain a strong following, he and Pericles, an influential statesman in Athens, held each other in mutual esteem, and Protagoras was assigned to write laws for the Athenian colony of Thurii, very likely in consequence of Pericles' influence (Sprague, p. 3). Plato may have intended to warn his readers not only against allowing their minds to become still, but also against allowing political leaders to dominate philosophical discourse without questioning them. It seems clear that Plato wants his readers to think for themselves.
In a recent blog entry, Matthew Silliman, a professor at Massachusetts College of Liberal Arts, asks, "What if, though neither perception nor true opinion with an account stands up to scrutiny, each of these alternatives could (dialogically, as it were) answer the limitations of the other?" (Silliman). This suggestion is based on the idea that the Theaetetus deals with an apparent incompatibility between theories that claim that knowledge must deal with static objects, and theories that claim that, in order to understand a changing world, people must be able to know things that change. The first corresponds to the idea that knowledge is true judgment, or true judgment with an account, and the second corresponds to the idea that knowledge is perception. While the first theory fails to explain how static objects relate to the changing world, the second is so inclusive that the term 'knowledge' becomes irrelevant to human experience, and the theory threatens to collapse into moral and epistemological relativism. Knowledge, if it is to exist, must take change into account, and also have some degree of stability.
This reading requires one to think beyond the explicit content of the Theaetetus. In this way, it takes to heart the idea that it is important and healthy for one to keep one's mind in motion, so to speak, rather than simply become complacent. This theory of knowledge acknowledges that static ideas offer an illusion of absolute certainty are inadequate to constitute knowledge, as well as is unmediated perception. In short, it suggests that people may have knowledge, even though knowledge claims may be misleading.
The Theaetetus addresses many enigmas, and it ends on an inconclusive note about its main object of inquiry, knowledge. Throughout the dialogue, rather than become frustrated about the difficulty of arriving at an answer, Socrates retains a very playful demeanor. At one point, Theodorus becomes slightly frustrated with Socrates, and accuses him of behaving like such devious murderers as Sciron and Antaeus in the way that he engages others in conversation. Socrates admits of a certain similarity, but insists that such behavior stems from a passion for exercise (169b-c). In his introduction to the Theaetetus, Lewis Campbell says:
The mind of Plato in the Theaetetus is keenly alive to the presence of logical difficulties, but is neither irritated nor deterred by them. He unravels them with the utmost patience, but at the same time treats them with a kind of compassionate irony, as if he refused to be bound within the framework of contemporary thought (p. lxxxvii).
The playfulness in the Theaetetus seems indeed to acknowledge uncertainty as something acceptable. In its open uncertainty, it nevertheless emphasizes the importance of active questioning. Lest one allow one's mind to come to a standstill, it encourages one to identify the 'wind eggs' in one's thoughts that may generate a false sense of certainty.
Works Cited
Campbell, Lewis. Philosophy of Plato and Aristotle: The Theaetetus of Plato. New York: Arno P., 1973
Plato. Theaetetus. Ed. Bernard Williams. Trans. M. J. Levett. Indianapolis, IN: Hackett Company, 1992.
Silliman, Matthew. "Theaetetus and a positive theory of knowledge?" Skeptiblog. 3 Mar. 2009. 25 Mar. 2009 .
Sprague, Rosamond Kent, ed. The Older Sophists. Columbia, SC: University of South Carolina P., 1972.
